Catheters are used in a wide variety of medical procedures. In some applications, these devices provide physicians the ability to explore, operate, and insert drugs/medical devices in various reaches of the anatomy without invasive surgery. Oftentimes, the catheters have medical devices mounted on the catheter shaft, such as in an electrophysiological (EP) ablation catheter, wherein an ablation electrode is mounted at a distal tip of the catheter. In another application, guiding catheters are used to create an easily navigable pathway to be used for delivery of various payloads such as drugs, therapeutic/diagnostic devices (e.g., EP mapping and ablation electrodes), and implantable devices (e.g., cardiac pacing/defibrillation leads).
Guiding catheter systems are typically configured with a profile that is optimized for the intended method of access. For example, when trying to access the coronary sinus of a patient's heart, one method is to enter the venous system through an incision at a large vein such as the subclavian vein near the shoulder. A guiding catheter is inserted through this incision and is displaced in an arced path through the superior vena cava into the right atrium of the heart. From the right atrium, the ostium of the coronary sinus must be located. A catheter with a distal contour including a relatively sharp bend will point the catheter towards the likely location of the coronary sinus once the right atrium is reached. The contours of pre-shaped guiding catheters are often fixed during manufacture.
A pre-shaped guiding catheter is sometimes used to blindly locate the coronary sinus ostium. This endeavor, however, is complicated by the fact that the location of the coronary sinus ostium may vary appreciably from one patient to another, especially among patients with diseased hearts. Further, the size and flexibility of the catheter that provides maneuverability through the convoluted access path becomes a disadvantage when trying to manipulate the distal end of the catheter in the right atrium.
The primary goal of a guiding catheter procedure is to locate and cannulate a vessel of interest safely and in the least amount of time. Finding and cannulating the coronary sinus, for example, can become a time consuming, trial and error procedure even in a healthy patient. Patients exhibiting symptoms of advanced heart disease can have blockages or deformations of heart structure, further complicating the task of locating the ostium.
Some common techniques are used to aid the physician in visualizing the distal end of a guiding catheter during cannulation. These techniques include the procedures of angiography and venography. The procedures involve injecting a radioopaque dye into the bloodstream to X-ray map blood vessels. Typically, the catheter is radioopaque as well in order to be clearly located. Although effective, this method requires exposing the patient to radiation, and therefore exposure times are necessarily limited. Further, injection of the dye can cause local thrombophlebitis, though this is now rare with modern contrast agents.
Another approach used in assisting catheter guidance is endoscopy, a technique using a fiber optic camera to visualize the blood vessel interior. This method can be effective, but is expensive and is not always adaptable to the geometries required of a guiding catheter intended for applications such as right heart access.
There is a need for an improved guiding catheter allowing quicker access to vessels such as the coronary sinus. There is a need for a simplified method of identifying such vessels and assisting a physician in cannulating a target vessel with a guiding catheter. The present invention fulfills these and other needs, and addresses other deficiencies of prior art implementations and techniques.